The media gateway controller (MGC) and the media gateway (MG) are two key components in a packet switched (PS) network. The MGC is responsible for the call control function, and the MG is responsible for the service bearer function. In this way, the call control plane is separated from the service bearer plane, thus fully sharing the network resources, simplifying equipment upgrade and service extension, and greatly reducing the development and maintenance costs.
FIG. 1 shows a networking diagram of the MGC and the MG. The widely used protocols for communication between an MGC and an MG include the Gateway Control Protocol (H.248) and the Media Gateway Control Protocol (MGCP). Taking H.284 as an example, various resources on the MG, for example, time division multiplexing (TDM) channels, and Real-time Transfer (RTP) protocol streams, are abstractly represented by terminations; and the combinations of terminations are abstractly represented by contexts. In this protocol-based abstract model, the call connection is actually an operation on a termination and a context. Such operations are performed through command requests and replies between the MGC and the MG. Commands include: Add, Modify, Subtract, Move, AuditValue, AuditCapabilities, Notify, and ServiceChange. Command parameters, also known as descriptors, are categorized into property, signal, event, and statistic. The parameters with service relevance are logically aggregated into a package.
In the H.248 protocol, the parameters related to quality of service (QoS) are generally defined as property parameters or statistic parameters. The statistic parameters are related to the QoS state, for example, the current value or average value applied by a jitter buffer. Such parameters are generally calculated and operated by the MG. The MGC can enable or disable them selectively, namely, activate or deactivate some or all of the statistic parameters.
Currently, the MGC obtains the current values of the statistic parameters on the MG in the two ways: (i) the MGC sends a request command (AuditValue or Subtract) to the MG, and specifies the expected statistic parameter values or applies the default statistic parameter values, and then the MG returns the current value of each statistic parameter to the MGC through a response command; or, (ii) the MGC specifies the conditions for reporting a statistic parameter to the MG, or the MG presets such conditions. When the current value of the statistic parameter meets the conditions, the MG reports the current value of the statistic parameter to the MGC.
In the prior art, if the MG is triggered to report the value of a statistic parameter to the MGC, the reported information contains only the current value of the parameter, without the information about the time of triggering the reporting. According to the received statistic parameter value, the MGC performs subsequent operations. If the time information is required in the analysis and prediction, the time information is subject to the time when the MGC receives the current value of the parameter. However, as affected by various factors such as protocol encoding/decoding, network transmission and message buffer, the time when the MGC receives statistic parameter values is different from the time when the reporting of these statistic parameter values is triggered according to the reporting conditions, and the time deviation is not fixed. This makes it impossible to obtain an accurate time error, thus reducing the accuracy of the subsequent analysis and prediction based on the time information.